Tuesday, April 15, 2014

The eschatology of lunar eclipses

Oh, when the moon turns red with blood

Oh, when the moon turns red with blood

I want to be in that number

When the saints go marching in

There are plenty of resources on the Internet where you can learn about lunar eclipses--what causes them, when they occur, why they are (sometimes) red, etc.--and I don't think I need to lay all of that out in detail for today's purposes. But I will draw your attention to a handful of facts, the importance of which will become apparent.

First, as I'm sure you are aware, the phenomenon of "moonlight" is actually sunlight reflected off the surface of the moon. At any given time, approximately half of the moon's surface is illuminated (just as half of the earth's surface is illuminated) by the sun. Depending on where the moon is in relation to the sun and the earth, we can see all, part, or none of the illuminated half. This is what is referred to as the "phases" of the moon--full moon (we see all of the illuminated part), gibbous moon (we see more than half the illuminated part), crescent moon (we see less than half the illuminated part), and new moon (we see none of the illuminated part).

The full moon occurs when the moon is on the side of the earth opposite the sun, because we have to be positioned between the moon and the sun in order to receive the reflected light from the full lunar surface.

Just as a person standing in sunlight casts a shadow, the earth casts a shadow into space. Occasionally, the moon's orbit carries it into that shadow, and the sun's light is (partially or completely) blocked. That means that there is no moonlight, so the moon seems to disappear. We refer to that as a lunar eclipse.

Thus, a lunar eclipse can only occur when the moon is on the side of the earth opposite the sun, because the earth has to be positioned between the moon and the sun in order to block the moon from getting sunlight.

Those two "thus"es, by the way, combine for an important observation: a lunar eclipse can ONLY occur at the full moon.

(We don't get a lunar eclipse at every full moon because the moon's orbit is somewhat tilted, and most of the time it "misses" the earth's shadow. Often, the lunar eclipse is only partial because the moon's orbit only partially carries it through the shadow.)

Last night's lunar eclipse was a full eclipse, and is the first in a set of four, called a "tetrad," that will occur over the next 16 months, without any partial eclipses in between. This is a fairly frequent occurrence when the tilt of the moon's orbit is as it is presently, but there can be long stretches without that arrangement.

By the way, lunar and solar eclipses always occur in pairs. There will be a solar eclipse on April 29, but it will only be visible in the southern hemisphere, mostly in Australia and Indonesia.

Last night's lunar eclipse is also called a "blood moon." During the eclipse, as the earth's shadow creeps across the moon's surface, the moon takes on a deep red color. This phenomenon is due to something called "Rayleigh scattering." When the moon is red, it's because the sunlight that gets to the moon is passing through the earth's atmosphere en route. It's the same phenomenon that causes red skies at dusk or dawn.

(You can perform a simple experiment with an aquarium, water, Pine-Sol, and a strong white light source, like a slide projector. Fill the aquarium with water, pour in and stir a generous amount of Pine-Sol to make it cloudy, and shine the light through the aquarium. The water nearest the light will appear blue, and that farthest away will appear red.)

The blood moon is important in Christian eschatology (belief in End Times) because of a verse of Joel:

The sun will be turned to darknessand the moon to bloodbefore the coming of the great and dreadful day of the Lord.

Joel 2:31

The problem, of course, is that the "blood moon" actually occurs with some frequency. In fact, virtually every total lunar eclipse could be said to be a "blood moon" because of the phenomenon that causes it.

John Hagee and other prominent pastors have been talking of late about End Times, referring to the blood moon, pointing out not only that these four blood moons in a row will all occur on Jewish festivals: two on Passover, two on Sukkot, in successive years. Hagee wrote a best-selling book about it, which proves, I suppose, that some people will buy anything.

The discussion of this coincidence is essentially of a piece with the supposed Lincoln-Kennedy connection, which have been thoroughly debunked.

The essential fact that you need to understand why this is actually just a coincidence, not a "sign": Passover and Sukkot occur on defined dates in the Hebrew calendar. Passover begins on 15 Nisan, and Sukkot begins on 15 Tishrei. The Hebrew calendar is a lunisolar calendar. It is based upon months that begin at the "new moon"--the day on which the first sliver of moon is visible in Israel.* In other words, the first day of a new month is at the new moon. And because the full moon is about two weeks after the new moon...presto: 15 Nisan and 15 Tishrei always occur at the full moon.

* - The "solar" part of lunisolar refers to the practice of adding months, periodically, to keep festivals in time with the seasons, which are determined by the position of the earth with respect to the sun.

And remember what else occurs at the full moon? Lunar eclipses.

This is simply a coincidence. There is a one-in-six chance that any given lunar eclipse will occur at the start of Passover or Sukkot--in ANY year. To have four in a row is simply not that unusual. And in fact, since the first century C.E., there have been 62 such tetrads, and eight of them have coincided with both feasts. That's fairly rare, but not so rare that we could reasonably argue for some sort of design or signal.

Now, I'm willing to tolerate people who want to believe in this kind of stuff. Just because I choose to apply critical thinking and evidentiary standards and don't believe in supernatural occurrences doesn't mean that others must conform to my views. It is entirely foreign to me to hope for the end of the world, but it is probably harmless to do so. But a red flag is raised for me when people use this kind of thing as a pretext for helping to usher in the end of the world. When you cross the line from passive to active intent, when you urge acts that you believe are foretold in the Bible in order to bring about the end of the world, then it is time to oppose that which we would ordinarily tolerate.